Equipment World Digital Magazine
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tier engine. If a contractor has a lot of mostly older machines, however, CARB may decide the contractor needs to put in a higher tier engine in an older piece of equipment, or scrap the old equipment and buy a new machine to reduce his total emissions output. "California has a plethora of regulations – from off-road, on- road, portable, stationary and ag – that drive the users to make hard decisions whether to replace or rebuild," says Glen Chrusciel, pro- gram manager, retrofit and repower at John Deere Power Systems. "Ini- tially it was a lot of rebuilds, taking Tier 1 machines and upgrading them to Tier 3. That was easy. Now as we're getting close to 2020, a lot of these milestones become difficult to meet. We're finding replacement of the whole machine to be the best bang for the buck." The goal of CARB and the EPA, says Schultz, is to reduce the num- ber of lower tier engines over time. In fact, engine vendors are required to destroy the older tier blocks they remove, by putting holes in them, taking a photo of the destroyed block and sending that and the se- rial number to the EPA. Keep in mind that it's not just California that restricts what you can do with a repower. So check with your state or local air quality officials before making a decision, buying an older piece of equipment or starting on any course of action. Technical challenges Putting a Tier 3 engine in older equipment designed for Tier 1 or Tier 2 engines isn't difficult. The designs of those engines changed little from tier to tier. And doing so in California may earn your fleet some emissions credits. But it is difficult to put a Tier 4 Interim or Tier 4 Final engine in most ma- chines powered by Tier 3 or earlier engines. "When we first started, we had a lot of Tier 1 and Tier 2 engines out there," says Terry Oftedal, program manager, engine application, con- struction and forestry division, John Deere Power Systems. "Depending on the vehicle platform, we could usually upgrade with minimum effort. But now that we're into the Tier 4 Interim and Tier 4 Final, the aftertreatment really changes the architecture of the vehicle as well as the electronic integration." Tier 4 Interim engines make substantial use of diesel particulate filters or DPFs. These large canisters take the place of the muffler, and filter out particulate matter from the exhaust. DPFs are so large that equipment manufacturers generally had to redesign their machines to get the DPFs and related plumbing to fit under the sheet metal. Most smaller Tier 4 Interim and Tier 4 Final engines (under 75 horsepower) have been able to avoid using a DPF, but they all con- tain a similar, if somewhat smaller, component, the diesel oxidation catalyst (DOC), which does much July 2017 | EquipmentWorld.com 36 maintenance | continued If you repower with engines in the same emissions tier, distributors often provide kits and engineering expertise to make this relatively simple.